1. Field of the Invention
The present invention relates to a power control assistance device for motor vehicles having an internal combustion engine. It is particularly suitable for controlling the speed and traction slippage of highway vehicles, but this application of the invention is to be understood as one non-limitative example of its potential uses.
2. Discussion of Related Art
The comfort and power of highway motor vehicles as well as traffic conditions in today's world make compliance with speed limits problematical. The driver who wants to maintain his vehicle at the maximum speed authorized while not violating the regulations is forced to pay great attention to his speedometer. A device capable of effectively assisting him in this task would be of great interest.
Prior devices for this purpose are known, among which three different principles of operation can be distinguished:
cruise controls: they maintain the speed stable despite changes in the layout of the road. PA1 excess-speed alarms: they signal the exceeding of the maximum speed by means of a luminous or acoustic alarm. PA1 speed limiters: they prevent exceeding the maximum speed, generally by positioning a movable stop on the power control. PA1 Cruise controls do not act as limiters and cannot be used in city traffic; they do not permit natural slowing down by release of the pedal and they are put out of operation by actuation of the brake or clutch; PA1 Alarms do not participate in automating the driving and they do not assist in maintaining the speed within a narrow range. PA1 Limiters have the drawback of keeping the speed of the vehicle in check, or of placing a hard point on the stroke of the pedal which the control means and the manner of action used make disagreeable for the driver and which is incompatible with the stabilizing of the speed. PA1 The measurement of the excess speed is made known to him by a direct perception which is related to his driving action; the return force on the spring is directly related to the speed difference. It is no longer necessary to observe the speedometer. PA1 The variations in intensity of this force are sufficient to assist the driver in effortlessly and unconsciously correcting the position of the accelerator pedal.
Apparatus based on these principles are little used, with the exception of cruise controls which the manufacturers offer as an option on high-class vehicles. French Patents 2 164 362, 2 537 742, 2 444 163, and 2 632 578 may be mentioned as representative examples.
These devices present problems which it is the object of the invention to solve, namely: